Improved block-electrical brush assembly



July 13, 1965 E R. PLASKO ETAL IMPROVED BLOCK-ELECTRICAL BRUSH ASSEMBLY2 Sheets-Sheet 1 Filed May 10, 1961 INVENTORS MAYNARD E-ANDERSON y EM.R- PLAS O MNEY July 13, 1965 E. R. PLASKO ETAL 3,194,931

IMPROVED BLOCK-ELECTRICAL BRUSH ASSEMBLY Filed May 10, 1961 2Sheets-Sheet 2 MAYNARD E. ANDERSON y 'EMIL R. PLASKO ATTORNEY- UnitedStates Patent 3,194,931 IMPROVED BLOCK-ELECTRICAL BRUSH ASSEMBLY Emil R.Plaslro, Walled Lake, and Maynard E. Anderson,

Southfield, Mich, assignors to American Radiator dz Standard SanitaryCorporation, New York, N.Y., a

corporation of Delaware Filed May 10, 1961, Ser. No. 109,174 1 Claim.(Cl. 200-466) This invention relates to electrical switch mechanisms,and to methods of manufacturing same. The mechanisms of the inventionare particularly applicable in delivering current to printed circuitboards in rotary program timers utilized to control the operation ofconventional domestic clothes washing machines. There are of courseother fields of application of the invention, such as in the relatedproblems of delivering current to analog-todigital encoders discs, andthe use of contact leaves in multi-contact relays.

One object of the invention is to provide a contact brush and method ofmanufacturing same, wherein a series of reed-like brush elements can bequickly and conveniently mounted in a di-electric block element at verylow cost.

A further object of the invention is to provide a mechanism and methodof manufacture wherein a series of lowcost cornmutating brush devicescan be accurately located in close tolerance relationship, withcomparatively small spacings between adjacent brushes, therebypermitting a large number of circuits to be completed in a comparatively small physical space.

A further object of the invention is to provide a contact brush andmethod of manufacturing same, wherein the individual brush elements maybe physically embedded in a di-electric mounting block and retainedtherein without danger of loosening or otherwise causing the brushassembly to have a shortened service life.

An additional object is to provide a contact brush assembly having thedesired features of low cost, quick assembly, excellent parts quality,satisfactory alignment of parts, sufficient contact pressure, relativelysmall spacing between adjacent contact brushes, and improved structuralstrength.

Other objects of the invention will be apparent from the followingdescription.

In the drawings:

FIGURE 1 is a plan view of an electrically conductive frame memberutilized in the practice of the invention;

FIG. 2 is a plan view with parts sectioned on line 2-2 in PEG. 3 andshowing the FIG. 1 frame after assembly thereof with a (ii-electricmounting block and after trimming off of certain excess frame portions;

FIG. 3 is an elevational view with parts thereof sectioned on line 33 inFIG. 2;

FIG. 4 is a plan view of another embodiment of the invention;

FIG. 5 is a sectional view taken substantially on line 55 in FIG. 4;

FIG. 6 is a plan view of a third embodiment of the invention; and

FIG. 7 is an elevational view of the FIG. 6 embodiment.

Referring in greater detail to the drawings, and particularly FIG. 1,there is shown therein an annular electrically conductive metal frame 10having elongated side portions 12 and 14 interconnected by web-formingand wall portions 16 and 18. Extending inwardly from respective ones ofend wall portions 16 and 18 are two sets of elongated parallel strips 20and 22. The end areas of these strips remote from wall portions 16 and18 are interconnected by short web walls 24 and 26, so that the entireframe 10 may be blanked from a single sheet of material BJMBH PatentedJuly 13, 1965 with the various strips and 22 accurately located innon-varying positions, i.e., the strips 20 and 22 are prevented frombending, twisting or wiggling while they are connected together by theweb portions 24 and 26.

Referring now to FIG. 2, the strips 20 and 22 are shown withintermediate portions 28 and 30 thereof embedded in the leg portions 32and 34 of the U-shaped di-electric block 36, said block having a webportion 38 interconnecting the two leg portions 32 and 34 to form arigid support for the two sets of conductive strips 20 and 22.

In constructing and assembling the strips 20 and 22 and block 36, thestrips are formed as part of the frame 10 (as in FIG. 1), after whichframe 10 may be placed as an insert in a mold cavity shaped to theconfiguration of block 36. Moldable di-electric material is then moldedaround the portions 28 and 30 of the brush-forming strips 2% and 22 sothat the strips become firmly anchored to the block leg portions 32 and34. Preferably, although not necessarily, the strip portions 28 and 30are apertured, as at 40, to insure a gool locking of the di-electricmaterial to the strips. After or before the block 36 is formed parts ofthe frame may be bent on lines to redirect the reedlike strips 20 and 22at angles to the general plane of the frame. Subsequent to the moldingoperation the various web portions 16, 18, 24 and 26 are separated ortrimmed from the strips 20 and 22 to form the assembly as shown in fulllines in FIG. 2. Preferably the bending step is performed prior to thetrimming step since the various strips tend to be more regular in theamount of bend imparted thereto if they are bent while still part of theframe.

As will be noted from FIG. 3 (full lines) the terminal ends 46 of thestrip portions 42 and 44 are V-shaped and are slightly out of line withone another. When the block 36 is mounted between a suitable supportsurface 45 and printed circuit surfaces 47 the strip portions 42 and 44-are deflected upwardly to the dotted line positions, 42a and 44a,respectively; and the V-shaped terminal end portions 46 are then alignedwith one another so that all of the terminal portions contact surfaces47 on a common line. This relationship is particularly advantageous whenthe mechanism is utilized in association with printed circuit boards inprogram timers of the types shown in copending applications, Serial Nos.106,697, filed May 1, 1961, now Patent No. 3,151,257 or 106,730, filedMay 1, 1961. In these types of circuit boards it is desirable that allof the board contacts be on a common line to simplify and facilitate thetimer design.

Referring now to the form of the invention shown in FIGS. 4 and 5, thereis provided a di-electric mounting block 40 having suitable openings 52and 54 molded therein to permit mounting screws, rivets or the like toextend therethrough. As best shown in FIG. 5, the mounting block isprovided with a relatively thick section 56 and a relatively thinsection 58 having a flat surface 60 formed thereon. A series of metallicelectrically conductive reedlike brushes 62 extend through the mountingblock 50, with end portions 64 of said brushes having their face areasin the general plane of surface 60 so as to be exposed for engagementwith conductor devices not shown.

Brushes 62 may be initially formed as part of a metallic frame havingthe webs 66 interconnecting the brushes adjaoent one of their ends andhaving the web walls 68 interconnecting the strips 62 at their otherends. The process of manufacturing the FIG. 4 construction involvesblanking the metallic frame, positioning the frame in the mold cavity ofa plastic molding apparatus, molding the (ii-electric block 50 aroundportions of the conductive frame, bending the brushes about a commonline 70, and trimming web portions 66 and 68 from the brushes. Thebending step at 70 may be performed prior to the trimming and moldingsteps if desired.

In use of the FIG. 4 construction the molded block 50 is mounted inplace so that the thin flat portion 58 is located in an area where itcan receive a female plug-on connector (not shown). Such connectors aregenerally provided with a series of U-shaped electrically conductivegripper devices; flange 58 is of a suf'rlcient thickness that when aconventional female connector is inserted thereon the U-shaped gripperportions engage the upper and lower surfaces of the flange. The U-shapedgrippers thus contact the exposed portions 64 of the brushes 62 forestablishing the desired electrical snap-on connection.

As with the previously described embodiment, the reedlike portion '72 ofeach brush 62 may be utilized to engage a printed circuit board (notshown) so that the device may serve to transmit current between thecircuit board and the aforementioned snap-on connector.

Referring now to the embodiment of the invention shown in FIGS. 6 and 7,there is provided a di-electric mounting block 7 6 having a hub portion78, and elongated arm portion $0, and a terminal portion 82. As shown inthe aforementioned application, Serial No. 106,697, the mounting blockmay be disposed with hub portion 76 located on the shaft of a programtimer and with the terminal portion 82 disposed within a notch on a wallof the timer housing. By this arrangement the mounting block is enabledto utilize structure of the timer for itsfixed positionment adjacentprinted circuit rotary timer disc or board 86. The mounting block hasembedded therein a series of electrically-conductive reed-like brushes3d arranged so that one end of each brush may engage the printed circuiton board 536 and so that the other end of each brush may engage theprinted circuit on a board 8d. As shown in dotted lines in FIG. 6, thevarious brushes 84 are initially formed as part of a frame having theweb portions 9t} adjacent one end of the brush strips and having webportions 92 interconnecting the other ends of the brush strips. Afterthe mounting block '76 has been molded around intermediate portions ofthe brush strips the web portions 90 and 5 2 are trimmed off. Thevarious brushes may then be bent on lines and 96 so that the oppositeend portions of the strips extend angularly obliquely in differentdirections relative .to the general plane of the block as denoted byimaginary line 98.

It will be noted from the drawings that the strips desig-' nated bynumeral 100 are relatively short and the strips designated by numeral192 are relatively long. Also, the strips 109 are bent about line 6 at arelatively large angle to plane 98, whereas strips 1432 are bent at alesser angle to imaginary plane 98. The arrangement is such that whenblock 76 is installed between printed circuit boards 86 and 88, thestrips 100 and R12 are automatically moved from the full line positionsto the dotted line positions, ldtia and 102:: respectively with surfaces104 and 1% thereof in firm pressure engagement with contact areas onboard 88. By forming each strip 162 longer than strip 105) the contactareas 184 and 196 are located on different lines, and the contact stripscan be placed closer together than would otherwise be possible.

The above description has illustrated three embodiments of theinvention, but it will be understood that the invention is capable ofpractice with other embodiments, and that variations in method andconstruction may be resorted to without departing from the spirit of theinvention as set forth in the appended claim.

We claim In a brush assembly for use With a printed circuit board: a onepiece molded di-electric block formed to include a relatively thickmounting portion and a relatively thin plug-on portion extendingtherefrom and adapted to receive a female connector, said plug-onportion having first and second closely spaced parallel flat facesformed thereon; a series of parallel spaced electrically-conductivestrips embedded in said block; said strips being formed of fiat thingage sheet material, and all of said strips having the longest crosssectional dimension of their embedded port-ions disposed in the sameplane; said strips having first portions thereof disposed in the planeof said first flat face of the plug-on portion, whereby to makeelectrical connection with connectors in the aforementioned femaleconnector; said strips having second portions extending through therelatively thick mounting portion, and third reed-likeelongated portionsextending freely of the block bent at an appreciable angle to the secondportions for swinging movement, whereby when the block is located in astationary position adjacent a rotary printed circuit board thereed-like portions are deformed by the board surface to effect pressureengagement between the board and the reed-like portions.

References Cited by the Examiner UNITED STATES PATENTS BERNARD A.GELHEANY, Primary Examiner. MAX L. LEVY, Examiner.

